This invention relates in general to an improved method and apparatus for liquid/solids separation and, in particular, to a liquid/solids separation system which separates solids material from an unclarified liquid in part by settling. The materials which settle from the unclarified liquid and a portion of the liquid are further processed to separate the remaining solids from the liquid to discharge dry solids material from the system.
More specifically, this invention relates to a liquid/solids separation system utilizing a settling clarifier to remove solids material suspended in a liquid through the introduction of chemicals and inert solids material to accelerate the settling rate or precipitation of the solids material from the liquid. The effluent discharged therefrom may be further processed, discharged, or recycled depending upon the nature of the effluent. The semi-solids material which is settled or precipitated from the unclarified liquid, referred to as sludge, is passed to a storage reservoir whereat this material is further processed in order to obtain predetermined uniform quantity of solids material in the sludge. The material from the storage reservoir is then discharged into a filtration system whereat the solids materials contained therein are utilized to form a filter cake on the septum of the system filters with the filtrate from the filtration system being discharged from the filter for further processing, disposal or reuse depending upon the nature of the liquid. The solids material is accumulated by the filters and periodically removed therefrom to be conveyed through a sludge drying system whereat the solids materials are further treated and discharged as dry waste material.
The many applications wherein it is desired to clarify liquids by removing solid material and/or chemical contaminants prior to discharging the liquid are of such varied nature that sequential processing steps must be employed in order to clarify the liquid and/or remove the solids materials. Depending upon the nature of the liquid, some such systems are utilized to clarify the liquid prior to discharge, for example, into sewers. With other types of contaminated liquids, the liquid is clarified for continuous use because the liquid cannot be discharged into sewer lines and/or the costs of the liquid or costs of liquid disposal render discharge economically unduly prohibitive.
In all liquid/solid separation systems, the most desirable manner for disposing of the solids materials removed by the system would be to dispose of these solids material in a dry form. The discharge of dry waste solids materials from the system provides for more economic operation. Dry solids materials may be readily disposed of and/or more easily handled for further processing depending upon the nature of the solids material and whether or not it is desirable to dispose of these materials or to subject them to further processing.
Due to the highly varied nature of the contaminated liquids, the amount of liquid discharged (flow rate) as well as the amount of solids materials contained in the liquid (percentage of solids), or both, may vary extensively. Any liquid/solids separation systems which are intended to receive unclarified liquid, clarifying the liquid and discharging the solids material as a dry waste discharge, must, therefore, be capable of handling a wide latitude of flow rates and percentages of solids material passing through the system.